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Neo_M660A GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
i
Copyright © Neoway Technology Co., Ltd 2014. All rights reserved.
No part of this document may be reproduced or transmitted in any form or by any means without prior
written consent of Shenzhen Neoway Technology Co., Ltd.
is the trademark of Neoway Technology Co., Ltd.
All other trademarks and trade names mentioned in this document are the property of their respective
holders.
Notice
This document is intended for system engineers (SEs), development engineers, and test engineers.
The information in this document is subject to change without notice due to product version update or
other reasons.
Every effort has been made in preparation of this document to ensure accuracy of the contents, but all
statements, information, and recommendations in this document do not constitute a warranty of any
kind, express or implied.
Neoway provides customers complete technical support. If you have any question, please contact
your account manager or email to the following email addresses:
Sales@neoway.com.cn
Support@neoway.com.cn
Website: http://www.neoway.com.cn
Neo_M660A GPRS Module Hardware User Guide
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Contents
About This Document ......................................................................................................... 1
1 Introduction to M660A ..................................................................................................... 1
1.1 Overview ..................................................................................................................................... 1
1.2 Block Diagram ............................................................................................................................ 1
1.3 Specifications .............................................................................................................................. 2
2 Pin Description and PCB Foot Print .............................................................................. 4
2.1 Specifications and Encapsulation ................................................................................................ 4
2.2 Pin Definition .............................................................................................................................. 5
2.3 PCB Foot Print ............................................................................................................................ 8
3 Interface Design................................................................................................................. 9
3.1 Power Supply and Switch Interfaces ........................................................................................... 9
3.1.1 VBAT ................................................................................................................................. 9
3.1.2 VDD_EXT ....................................................................................................................... 12
3.1.3 VRTC ............................................................................................................................... 12
3.1.4 Power On/Off Procedure .................................................................................................. 13
3.1.5 RESET .............................................................................................................................. 15
3.2 UART ........................................................................................................................................ 16
3.3 USB Interfaces .......................................................................................................................... 18
3.4 DTR and RING ......................................................................................................................... 19
3.4.1 DTR Pin ........................................................................................................................... 19
3.4.2 RING Signal Indicator...................................................................................................... 19
3.5 SIM Card Interface .................................................................................................................... 20
3.6 Running LED Indicator ............................................................................................................. 22
3.7 Audio Interface .......................................................................................................................... 23
3.8 RF Interface ............................................................................................................................... 25
3.8.1 RF Design and PCB Layout ............................................................................................. 25
3.8.2 Recommended RF Connection ......................................................................................... 26
4 Electric Features and Reliability................................................................................... 27
4.1 Electric Feature ......................................................................................................................... 27
4.2 Temperature ............................................................................................................................... 27
4.3 Current....................................................................................................................................... 28
4.4 ESD Protection .......................................................................................................................... 28
5 RF Features ....................................................................................................................... 30
5.1 Work Band ................................................................................................................................. 30
5.1.2 Transmitting Power .......................................................................................................... 30
5.1.3 Receiving Sensitivity ........................................................................................................ 31
6 Mounting the Module onto the Application Board.................................................. 32
7 Package .............................................................................................................................. 32
Neo_M660A GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
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Table of Figures
Figure 2-1 Top view of the M660A module ............................................................................................ 4
Figure 2-2 PCB foot print recommended for M660A (unit: mm) ........................................................... 8
Figure 3-1 Current peaks and voltage drops ............................................................................................ 9
Figure 3-2 Reference design d for the power supply ............................................................................. 10
Figure 3-3 Reference design of power supply control ........................................................................... 10
Figure 3-4 Reference design of power supply controlled by p-MOSFET ..............................................11
Figure 3-5 Reference designs of separated power supply ...................................................................... 12
Figure 3-6 VRTC reference design ........................................................................................................ 13
Figure 3-7 Turning on procedure ........................................................................................................... 13
Figure 3-8 Turning off procedure .......................................................................................................... 14
Figure 3-9 Reference circuit for ON/OFF controlled by low level ........................................................ 14
Figure 3-10 Reference circuit for power-on controlled by high level .................................................... 15
Figure 3-11 Reset circuit with triode separating .................................................................................... 15
Figure 3-12 Signal connection between DCE and DTE ........................................................................ 16
Figure 3-13 Recommended communication circuit between 3.3V MCU and UART ........................... 17
Figure 3-14 Recommended communication circuit between 5V MCU and UART .............................. 17
Figure 3-15 USB circuit ........................................................................................................................ 18
Figure 3-16 RING indicator for incoming call ...................................................................................... 20
Figure 3-17 RING indicator for SMS .................................................................................................... 20
Figure 3-18 Reference design of SIM card interface ............................................................................. 21
Figure 3-19 Reference of SIM card socket ............................................................................................ 21
Figure 3-20 LED indicator directly driven by high level ....................................................................... 22
Figure 3-21 LED indicator driven by transistor ..................................................................................... 22
Figure 3-22 Reference design of MIC differential connections ............................................................. 23
Figure 3-23 Reference design for common audio input ........................................................................ 24
Figure 3-24 Reference design for receiver output ................................................................................. 24
Figure 3-25 Coupling capacitor interfacing ........................................................................................... 25
Figure 3-26 Reference design for antenna interface .............................................................................. 25
Figure 3-27 RF layout reference ............................................................................................................ 26
Figure 3-28 Encapsulation specifications of Murata RF connector ....................................................... 26
Figure 3-29 RF connections................................................................................................................... 26
Neo_M660A GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
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Table of Tables
Table 1-1 M660A specifications .............................................................................................................. 2
Table 2-1 M660A pin definition .............................................................................................................. 5
Table 3-1 Power supply and switch interface .......................................................................................... 9
Table 3-2 UART .................................................................................................................................... 16
Table 3-3 USB interface ........................................................................................................................ 18
Table 3-4 DTR and RING pins .............................................................................................................. 19
Table 3-5 SIM card interface ................................................................................................................. 20
Table 3-6 LED indicator ........................................................................................................................ 22
Table 3-7 Audio interface ...................................................................................................................... 23
Table 4-1 Electric feature of the module ............................................................................................... 27
Table 4-2 Temperature Feature .............................................................................................................. 27
Table 4-3 Current feature ....................................................................................................................... 28
Table 4-4 ESD feature of the module .................................................................................................... 29
Table 5-1 Work band ............................................................................................................................. 30
Table 5-2 Transmitting power (GSM850&EGSM900) ......................................................................... 30
Table 5-3 Transmitting power (DCS1800&PCS1900) .......................................................................... 30
Neo_M660A GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
1
About This Document
This document defines the features, indicators, and test standards of the M660A module and provides
reference for the hardware design of each interface. With Neo_M660A GPRS Module AT Command Set, this
user guide can help you complete wireless communication application easily.
1 Introduction to M660A
M660A is a compact wireless GSM/GPRS module that supports downlink EDGE. It can provide functions
of high-quality voice, SMS, and data services and is widely used in industrial and consumer fields.
1.1 Overview
Neoway M660A module adopts 68-pin LCC encapsulation and its dimensions are 24 mm x 24 mm x 2.6
mm, which can meet most customers' requirements. It provides customers the following hardware resources
and features:
UART interfaces, used for data communication, firmware updating and commissioning, and
supporting hardware flow control
Audio interfaces, including one line of MIC input (differential) and one line of receiver output
(differential)
10-bit ADC input, voltage ranging from 0 V to 2.8 V
One line of SIM card interface, compatible with 1.8 V and 3.0V SIM card
RING/LIGHT/DTR (sleep mode) functions
Time updating and timing power-on/off
Firmware updating via USB interface
1.2 Block Diagram
The M660A module consists of baseband controller, Flash ROM, RF section, application interfaces, etc. All
sections coordinate with each other to provide such communication functions as GPRS data and voice.
The following figure shows the block diagram of M660A.
Neo_M660A GPRS Module Hardware User Guide
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VBAT
VRTC
Digital
Interface
USB
SIM
UART
ON/OFF
Power
Manager
RF transceiver
FLASH
Digital
Baseband
Analog
Baseband
26 MHz CrystalRF Front-end-module
Audio
Interface
MIC
SIM PC
ADC
REC
1.3 Specifications
Table 1-1 M660A specifications
Specifications
Description
Band
GSM850/EGSM900/DCS1800/PCS1900 MHz dual-band/quad-band
Supporting band locking
Sensitivity
< -107 dBm
Max. transmit power
GSM850/EGSM900 Class4(2W)
DCS1800/PCS1900 Class1(1W)
Protocol
Supporting GSM/GPRS Phase 2/2+
AT
GSM07.07
Extended AT commands
Audio
Supporting the following audio coding:
HR
FR
EFR
AMR
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Supporting echo suppression
Supporting recording and DTMF check function
SMS
TEXT/PDU
Supporting SMS message receiving and sending and ring for new SMS
messages
Supporting SMS message management: reading/deleting/storage/list
GPRS feature
GPRS CLASS 12
Max. theoretic uplink rate: 85.6 Kbit/s
Max. theoretic downlink rate: 85.6 Kbit/s
Built-in TCP/IP protocol, supporting multiple links
Supporting server and client modes
Circuit Switch Data
CSD
USSD
Supplementary
service
Call forwarding
Call waiting
Call holding and multi-way calling
UART
Supporting hardware flow control, RTS and CTS controlled via AT commands
Supporting multiplexing
Supporting AT sending, data transmission, and software download
Supporting baudrate from 1200 bit/s to 115200 bit/s
RTC
Supporting real-time clock and time updating
Supporting timing power-on/off
CPU
ARM7-EJ@360MHz
Antenna feature
50 Ω impedance
Operating
temperature
-40℃ to +85℃
Operating voltage
3.5 V to 4.3 V (3.9 V is recommended)
Peak current
Max 2.0 A
Idle current
18 mA
Current in sleep
mode
< 2 mA (live network)
< 1 mA (instrument, DRX=9)
Neo_M660A GPRS Module Hardware User Guide
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2 Pin Description and PCB Foot Print
2.1 Specifications and Encapsulation
Specifications
M660A
Dimensions
24 mm x 24 mm x 2.6 mm (H x W x D)
Weight
2.6 g
Encapsulation
68-pin LGA
Figure 2-1 Top view of the M660A module
M660A
（TOP VIEW）
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
34
33
32
31
30
29
28
27
26
25
24
23
22
21
20
19
18
51
50
49
48
47
46
45
44
43
42
41
40
39
38
37
36
35
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
ON/OFF
GND
DTR
RING
NC
NC
CTS
RTS
UTXD
URXD
NC
NC
NC
NC
VDD_EXT
RESET
GND
NC
SIM_RST
SIM_CLK
SIM_DATA
VSIM
GND
USB_DM
USB_DP
VRTC
ADC_IN
VBUS
NC
RECN
RECP
MICN
MICP
GND
NC
NC
NC
NC
NC
GND
GND
NC
NC
NC
NC
NC
GND
NC
NC
NC
NC
LIGHT
NC
GND
VBTA
VBAT
VBAT
GND
GND
GPRS_ANT
GND
GND
GND
GND
GND
NC
NC
NC
11
USB
NC
POWER GND SIM UART
AUDIO ADC ANT OTHERS
Neo_M660A GPRS Module Hardware User Guide
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2.2 Pin Definition
Table 2-1 M660A pin definition
Pin
Name
I/O
Function
Reset
Status
Level Feature
(V)
Remarks
Power Supply and Switch Interfaces
55, 56,
57
VBAT
P
Main power supply
input
3.5 V to 4.3 V
(3.9 V is
recommended)
15
VDD_EXT
P
2.8 V power supply
output
Supply power for
IO level shifting
circuit.
Load capability:
less than 50 mA
26
VRTC
P
RTC power supply
2.8 V, maximum
output charging
current 2 mA
2, 17,
18, 29,
39, 45,
46, 53,
54, 58,
59,
61-65
GND
P
Ground
1
ON/OFF
DI
ON/OFF control input
I/PU
0<VIL<0.6
2.1<VIH<VBAT
Low level pulse
can change the
ON/OFF state.
16
RESET
DI
Reset input
Internal 2.8V
pull-up
Low level reset
Audio Interface
19
MICP
AI
Positive electrode of
differential MIC
output
Vpp≤200 mV
20
MICN
AI
Negative electrode of
differential MIC
output
21
RECP
AO
Positive electrode of
differential receiver
output
32 Ω receiver
driving output
22
RECN
AO
Negative electrode of
differential receiver
output
UART Interface
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7
CTS
DI
Clear to send
I/PU
0<VIL<0.6
2.1<VIH<3.1
0<VOL<0.42
2.38<VOH<2.8
With internal
47K resistors to
respectively pull
CTS and URXD
up to 2.8 V
8
RTS
DO
Request to send
I/PU
9
UTXD
DO
UART data transmit
O/PU
10
URXD
DI
UART data receive
I/PU
SIM Card
30
VSIM
P
SIM card power
supply output
0<VIL<0.25*VSI
M
0.75*VSIM<VIH
<VSIM
0<VOL<0.15*VS
IM
0.85*VSIM<VOH
<VSIM
Compatible with
1.8/3.0 V SIM
card
31
SIM_DATA
DI/O
SIM card data I/O
0<VIL<0.6
2.1<VIH<3.1
0<VOL<0.42
2.38<VOH<2.8
33
SIM_CLK
DO
SIM card clock output
32
SIM_RST
DO
SIM card reset output
LED Indicators
52
LIGHT
DO
Status LED
I/PD
2.8 V/4 mA
output
Sleep Mode Controlling
3
DTR
DI
Sleep mode
controlling input
I/PD
0<VIL<0.6
2.1<VIH<3.1
0<VOL<0.42
2.38<VOH<2.8
Low level by
default
Used together
with AT
commands
SMS and Incoming Call Ring
4
RING
DO
Ring output
I/PD
0<VIL<0.6
2.1<VIH<3.1
0<VOL<0.42
2.38<VOH<2.8
Detect incoming
SMS messages or
calls
ADC Detecting
25
ADC_IN
AI
10-bit ADC input
Detectable
voltage range: 0
V to 2.8 V
GPRS Antenna
60
GPRS_ANT
AI/O
GPRS antenna
interface I/O
50 Ω impedance
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USB Interfaces
24
VBUS
AI
USB voltage test
27
USB_DP
DI/O
USB interface
differential data cable
Complying with
the USB1.1
standard
Used for
firmware
download
28
USB_DM
DI/O
Reserved Pins
5, 6,
11~14,
23,
34~38,
40~44,
47~51,
66~68
NC
Must be left
disconnected.
Cannot connect
to power supply
or ground.
P: indicates power supply pins
NC: indicates pins that are not supported and must not be connected
DI: indicates digital signal input pins
DO: indicates digital signal output pins
I/PD: indicates digital signal input pins with pull-down
I/PU: indicates digital signal input pins with pull-up
AI: indicates analogy signal input pins
AO: indicates analogy signal output pins
The maximum input voltage at all IO ports (including peak signal current) cannot exceed 3.1 V because
the module uses a 2.8 V IO power system. In the application of the module, the IO output voltage from the
3.3 V power supply system of the external circuit might greatly overshoot 3.1 V due to the signal integrity
design. In this situation, the IO pins of the module might be damaged if the IO signals are connected to the
IO port on the 2.8-V system. To rectify this issue, take measures to match the level. For details, see the 3.2
UART.
Neo_M660A GPRS Module Hardware User Guide
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2.3 PCB Foot Print
LCC packaging is adopted to package the pins of the M660A module. Figure 2-2 shows the recommended
PCB foot print.
Figure 2-2 PCB foot print recommended for M660A (unit: mm)
1.004.00
4.00
24.00
24.00
12.00
3.78
4.97
1.60
0.60
4.4
4.4
2.4
1.30
3.03
Keepout Area A
Keepout Area B
No trace or copper is allowed in the keepout aera.
Neo_M660A GPRS Module Hardware User Guide
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3 Interface Design
3.1 Power Supply and Switch Interfaces
Table 3-1 Power supply and switch interface
Pin Name
I/O
Function
Remarks
VBAT
P
Main power supply input
3.5 V to 4.3 V (3.9 V is recommended)
VDD_EXT
P
2.8 V power supply output
Loading capability < 50 mA
VRTC
P
RTC power supply input
2.8 V, 2 mA at most
ON/OFF
DI
ON/OFF input
Triggered by low level
RESET
DI
Module reset input
Triggered by low level
Keep more than 100 ms
3.1.1 VBAT
VBAT is the main power supply of the module. Its input voltage ranges from 3.5 V to 4.3 V and the
preferable value is 3.9V. In addition to digital signals and analog signals, it supplies power for RF power
amplifier.
The performance of VBAT is a critical path to module's performance and stability. The peak input current at
the VBAT pin can be up to 2 A when the signal is weak and the module works at the maximum transmitting
power. The voltage will encounter a drop in such a situation. If the voltage drops lower than 3.5 V, the
module might restart.
Figure 3-1 Current peaks and voltage drops
Keep above 3.5 V
3.5 V
0 ms 3.7 ms 7.4 ms 10.7 ms T
2 A
Voltage
Input
current
3.9 V
Neo_M660A GPRS Module Hardware User Guide
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Figure 3-2 shows a recommended power supply design for the module.
Figure 3-2 Reference design d for the power supply
Power Supply GPRS Module
Close to the pin of the module
D1 C1 C2 C3 C4
VBAT
Current testing point
I_max
C5
In the circuit, you can use TVS at D1 to enhance the performance of the module during a burst. SMF5.0AG
(Vrwm=5V&Pppm=200W) is recommended. A large bypass tantalum capacitor (220 μF or 100 μF) or
aluminum capacitor (470 μF or 1000 μF) is expected at C1 to reduce voltage drops during bursts together
with C2 (10 μF capacitor). In addition, you need to add 0.1 μF, 100 pF, and 33 pF filter capacitors to enhance
the stability of the power supply.
A controllable power supply is preferable if used in harsh conditions. The module might fail to reset in
remote or unattended applications, or in an environment with great electromagnetic interference (EMI). If
you adapt 5 V power supply, you can use the EN pin on the LDO or DC/DC chipset to control the switch of
the power supply as shown in Figure 3-3.
MIC29302WU in the following figure is an LDO, which can output 3 A current.
Figure 3-3 Reference design of power supply control
VCC_IN_5V
GPRS_EN VBAT
100 uF
TAN 0.1 uF
TVS
5V
0.1 uF
470 uF
TAN
EN
VIN
VOUT
ADJ
MIC29302WU
10K 4.75K
2
164
5
3
The alternative way is to use a p-MOSFET to control the module's power supply, as shown in Figure 3-4.
When the external MCU detects the exceptions such as no response from the module or the disconnection of
GPRS, power off/on can rectify the module exceptions.
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Figure 3-4 Reference design of power supply controlled by p-MOSFET
VCC_IN_3.9V VBAT
10K
100K 33 pF
10 uF
GPRS_EN
2K
10K
0.1 uF
Q1
R4
C1 C2 C4 C5 C7
R1
R2
10 uF 0.1 uF R3
Q2
TVS
5V 470 uF
C3 C6
100pF
S
G
D
In Figure 3-4, the module is powered on when GPRS_EN is set to high level.
Q2 is added to eliminate the need for a high enough voltage level of the host GPIO. In case that the GPIO
can output a high voltage greater than VCC_IN_3.9V - |VGS(th)|, where VGS(th) is the Gate Threshold Voltage,
Q2 is not needed.
Reference components:
Q1 can be IRML6401 or Rds(on) p-MOSFET which has higher withstand voltage and drain current.
Q2: a common NPN transistor, e.g. MMBT3904; or a digital NPN transistor, e.g. DTC123. If digital
transistor is used, delete R1 and R2.
C3: 470 μF tantalum capacitor rated at 6.3 V; or 1000 μF aluminum capacitor. If lithium battery is
used to supply power, C3 can be 220 μF tantalum capacitor.
Protection
Place a TVS diode (VRWM=5 V) on the VBAT power supply to ground, especially in automobile
applications. For some stable power supplies, zener diodes can decrease the power supply overshoot.
MMSZ5231B1T1G from ONSEMI and PZ3D4V2 from Prisemi are options.
Trace
The trace width of primary loop lines for VBAT on PCB must be able to support the safe transmission of 2A
current and ensure no obvious loop voltage decrease. Therefore, the trace width of VBAT loop line is
required at least 2 mm and the ground should be as complete as possible.
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Separating
As shown in Figure 3-1, the GPRS module works in burst mode that generates voltage drops on power
supply. And furthermore this results in a 217 Hz TDD noise through power (One of the way generating
noise. Another way is through RF radiation). Analog parts, especially the audio circuits, are subjected to
this noise, known as a "buzz noise" in GSM systems. To prevent other parts from being affected, it's better
to use separated power supplies. The module shall be supplied by an independent power, like a DC/DC or
LDO. See Figure 3-5.
DC/DC or LDO should output rated peak current larger than 2 A.
The inductor used in Reference Design (b) should be a power inductor and have a very low resistance. 10
μH with average current ability greater than 1.2 A and low DC resistance is recommended.
Figure 3-5 Reference designs of separated power supply
Other circuit
DC-DC/LDO
GPRS
module
DC-DC/LDO
Power
Input
Other circuitDC-DC/LDO
GPRS
module
Power
Input 10 uH
Reference Design (a) Reference Design (b)
EMC Considerations
Place transient overvoltage protection components like TVS diode on power supply, to absorb the power
surges. SMAJ5.0A/C could be a choice.
Never use a diode to make the drop voltage between a higher input and module power. Otherwise,
Neoway will not provide warranty for product issues caused by this. In this situation, the diode will
obviously decrease the module performances, or result in unexpected restarts, due to the forward voltage
of diode will vary greatly in different temperature and current.
3.1.2 VDD_EXT
It is recommended that VDD_EXT is only used for interface level shifting. VDD_EXT can output 2.8 V and
50 mA. It stops output after the module is shut down.
3.1.3 VRTC
VRTC is the external power supply pin of RTC inside the module. It can be connected to external battery or
supercapacitor. When VBAT works properly, VRTC outputs 2.8 V and maximum 2 mA and can be
connected to battery or supercapacitor to charge. When VBAT is disconnected, the module can discharge
the battery or capacitor to supply power for RTC circuit in short time. Leave this pin disconnected if not
used.
0 shows the reference design of the VRTC power supply.
Neo_M660A GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
13
Figure 3-6 VRTC reference design
Backup
battery
GPRS Module
RTC
Circuit
Capacitor
VRTC
3.1.4 Power On/Off Procedure
Prior to turning on the module, power on the host MCU and finish the UART initialization. Otherwise
conflictions may occur during initialization, due to unstable conditions.
ON/OFF is a low level pulse active input, used to turn on or off the module.
Turning on the Module
While the module is off, power on the module, drive the ON/OFF pin to ground for at least 1.2 second and
then release. The module starts. After the module is started up, keep the ON/OFF pin at high level. The
UART port will send an unsolicited message (MODEM:STARTUP), indicating the powering on of the
module and can respond to the AT commands.
When you design your program, you can use the unsolicited message (MODEM:STARTUP) to check
whether the module is started or reset improperly.
Figure 3-7 shows the procedure of powering on the module.
Figure 3-7 Turning on procedure
VBAT
ON/OFF
VDD_EXT
UART
1.2s
3s
300 ms
/
